1. Field of the Invention
The present invention relates to motor vehicle door locks and more particularly to locks which can be locked/unlocked electrically from the outside and/or from the inside.
2. Description of the Related Art
Such locks comprise, as is known, a forked latch intended to cooperate with a striker, a pawl which normally locks the latch in the closed position, a latch-release mechanism comprising a control member which experiences an actuating movement in response to actuation of a handle of the corresponding door of the motor vehicle by the user. The control member may adopt an active position for which it acts, during its actuating movement, on the pawl in order to place it in an xe2x80x9cescapedxe2x80x9d or xe2x80x9cnonobstructingxe2x80x9d position (in which said pawl releases the latch), and an inhibited position in which said control member, during its actuating movement, has no effect on said pawl. The lock further comprises an electromechanical locking/unlocking device which responds at least to an unlocking signal by moving said control member from its inhibited position into its active position.
Vehicle door closure systems in which the unlocking signal is generated by actuation of a lock cylinder are known. In other known systems, this unlocking signal is provided by an electronic recognition device in response to an infrared remote-control or radioelectric remote-control signal produced by the user using an appropriate remote control. With these known systems, if the lock is in a locked condition, that is to say if the control member which forms part of the latch-release mechanism is in its inhibited position, two successive actions are then needed in order to open the door: first of all, the lock has to be unlocked using an appropriate means (key, remote control, etc.), then the door has to be opened, for example by pulling on its exterior handle.
It is clear that, when the vehicle is in frequent use, the fact of always having to perform two actions in order to unlock the door and access one""s vehicle may be seen as a drawback. Furthermore, insofar as these known systems require the use either of a key or of a remote control, which takes up one of the user""s hands, this may also be seen as an encumbrance.
This is why so-called xe2x80x9chands-free vehicle accessxe2x80x9d systems have already been proposed, these being supposed to allow a user to open a door of his or her vehicle directly by a single action on the exterior handle of the corresponding door, regardless of whether the lock of said door is in the locked or in the unlocked condition, and for this to be achieved without having a key, a remote control or any similar device in his or her hand for unlocking the lock. To this end, these known systems are equipped with an electronic recognition device fitted with a radio emitter and designed to be able to dialog with a radioelectric device, known as the xe2x80x9celectronic tagxe2x80x9d incorporated into a wristwatch, a credit card, a badge or the like worn or carried by the user. The electronic recognition device does not produce its unlocked signal until it has identified correct ownership.
In such known so-called hands-free access systems, the transmission of the unlocking signal which controls the electromechanical locking/unlocking device, on the one hand, and the actuation of the release mechanism, on the other hand, take place simultaneously. Now, the difference between the relatively long response time of the electromechanical device and the very short response time of the release mechanism is such that said control member, which forms part of the latch-release mechanism, has often completed its actuating movement even though it has not yet been brought into the active position by the electromechanical locking/unlocking device. This means that the user""s first action on the door handle does not cause the door to open and that said user has to operate said handle again in order to cause the door to open. This need to operate the door handle twice is obviously a drawback for a system which was supposed to allow the door to be opened in a single action.
French patent application No. 98/05604 filed on May 4, 1998, and corresponding U.S. patent application Ser. No. 09/127,765, entitled xe2x80x9cElectrically locked motor vehicle door lockxe2x80x9d, filed on Jul. 31, 1998, in the name of Hochart et al. and assigned to the same assignee as the present application suggests two solutions for overcoming this drawback. These two solutions consist in using an opening catch-up means which, when the unlocked signal is transmitted roughly at the end of the actuating travel of the control member, brings the pawl into its xe2x80x9cescapedxe2x80x9d position. In concrete terms, in these two known solutions, the control member which acts on the pawl to make it move into its xe2x80x9cescapedxe2x80x9d position or an actuating lever, which also forms part of the latch-release mechanism, is configured in such a way as to have a ramped-shaped surface portion which is inclined with respect to the direction of the movement of the control member and which, at the end of the actuating travel of said control member, acts directly or indirectly, according to whether it is the first or second aforementioned solution, in the manner of a cam on the pawl so as to cause it to move into xe2x80x9cescapedxe2x80x9d position.
The object of the present invention is therefore to provide a solution for avoiding the user having to exert two actions on the door handle with a view to opening this door, and to do so without having to use an excessively powerful electric actuating device for unlocking the lock and causing the pawl to move into its xe2x80x9cescapedxe2x80x9d position.
To this end, the invention provides an electrically locked/unlocked lock for a hands-free access motor vehicle door, comprising:
a) a forked latch intended to interact with a striker;
b) a pawl which locks the latch in the closed position and which can adopt an xe2x80x9cescapedxe2x80x9d position in which it no longer acts on the latch;
c) a mechanism for releasing the latch, including a member for operating from the outside which can undergo an actuating movement in response to actuation of a handle on the outside of said door by a user and which, in a condition in which the lock is unlocked from the outside, can, during its actuating movement, act on the pawl to bring it into said xe2x80x9cescapedxe2x80x9d position;
d) an electromechanical locking/unlocking device including an electric device for actuating from the outside which reacts at least to a signal for locking or unlocking from the outside, so as to cause the lock to move into said condition in which it is locked or unlocked from the outside;
e) an electronic recognition device capable of producing said unlocking signal when it receives an appropriate control signal from, for example, a remote control or an appropriate electronic tag device worn or carried by the owner of the vehicle or by an authorized user;
characterized in that this lock furthermore comprises an energy accumulation device which includes a spring means and which is interposed between said control member and said pawl in such a way that when the lock is in the condition in which it is locked from the outside, said spring means stores up energy by being stressed by said control member during its actuating movement in response to actuation of said exterior door handle and so that when the lock passes into the condition in which it is unlocked from the outside, in response to said unlocking signal, roughly at the end of the actuating travel of said control member, the energy stored up in said spring means is released and the energy accumulation device causes said pawl to move into its xe2x80x9cescapedxe2x80x9d position.
This being the case, when the electronic recognition device identifies the correct owner or an authorized user and when the latter pulls on the door handle, the pawl is automatically brought into its xe2x80x9cescapedxe2x80x9d position and the latch is released, by virtue of the xe2x80x9cfreexe2x80x9d energy stored up in the spring means when actuating the door handle. The result of this is that the electric drive device designed to lock/unlock the lock and consisting, for example, of an electromagnet or of an electric motor, can be of a smaller size and power because it is no longer used to cause the pawl to move into its xe2x80x9cescapedxe2x80x9d position to release the latch, but only to unlock the lock.
In one embodiment of the present invention, said energy accumulation device includes a first pivoting lever which is attached to said control member and pivots about a first axle under the action of said control member, a second pivoting lever which is mounted so that it can pivot on said first axle and which cooperates with the pawl so as to carry it along with it in its pivoting movement, and said spring means which is mounted between the two pivoting levers.
When the lock is in the condition in which it is unlocked from the outside, the electromechanical locking/unlocking device couples the first and second pivoting levers together in such a way that they pivot together about said first axle under the action of said control member. When the lock is in the condition in which it is locked from the outside, said electromechanical locking/unlocking device prevents the second lever from pivoting so that the spring means is stressed by the first lever when it pivots under the action of said control member.
In one embodiment of the invention, the second pivoting lever may have first and second tabs which are spaced apart in a tangential direction with respect to the pivoting movement of said second lever and which project from one face of this second lever some distance from said first axle. The second lever also has a first oblong slot which extends in the longitudinal direction of the second lever between said first axle and the first and second tabs.
In this embodiment, the first pivoting lever passes between the first and second tabs of the second pivoting lever and has a third tab which projects from one face of this first lever some distance from said first axle and which rests against the first tab of the second lever when there is no action on the door handle. The first pivoting lever also has a roughly L-shaped second slot with two parts, one of the two parts of which coincides with the first oblong slot of the second lever when said third tab is resting on said first tab. Said spring means may then be arranged between said second and third tabs, and may consist of a helical spring.
The electromagnetic locking/unlocking device may comprise a lever for locking from the outside which is coupled to the electric device for actuating from the outside and which is mounted so that it can pivot on a second axle which is parallel to said first axle. In this case, the lever for locking from the outside may have an immobilizing finger which, when the lock is in the condition in which it is locked from the outside, cooperates with the second tab of the second pivoting lever to prevent the latter from pivoting. As a preference, when the lock is in the condition in which it is locked from the outside, said first and second tabs of the second pivoting lever, said immobilizing finger and the center of said second axle are aligned.
The electromechanical locking/unlocking device may further comprise a link rod, a first end of which is coupled to the first and second pivoting levers by a first stub which is engaged in the first and second slots of said first and second pivoting levers and causes them to rotate as one when the lock is in the condition in which it is unlocked from the outside. The second end of the link rod is coupled to said locking lever by a second stub which is engaged in a third oblong slot made in this locking lever. This third slot is at lease approximately aligned with the first oblong slot of the second pivoting lever when the lock is in the condition in which it is unlocked from the outside. The second stub is able to move in the third slot against the return force of a spring which urges the link rod in one direction such that its first stub comes to be positioned at that one of the two ends of said first oblong slot which is furthest from said first axle.
Advantageously, the electromechanical locking/unlocking device comprises an electrical device for actuating from the inside which reacts to a signal for unlocking from the inside so as to cause the lock to move into a condition in which it is unlocked from the inside, in which lock, actuation of an interior door handle by a user acts on the latch-release mechanism to bring the pawl into the escaped position, and reacts to a signal to lock from the inside, to cause the lock to pass into a condition in which it is locked from the inside, in which condition of the actuation of the interior door handle and of lock stalk have no effect on the release mechanism, said electromechanical locking/unlocking device comprising a lever for locking from the inside which is coupled to said electrical device for actuating from the inside, said lever for locking from the inside being mounted so that it can pivot on an axle and having a first oblong aperture, roughly in the shape of an arc of a circle, through which there passes a drive peg which is also received in a second oblong aperture extending roughly at right angles to the first oblong aperture, in the lever for locking from the outside, so that pivoting of either said lever for locking from the inside or said lever for locking from the outside causes the free sliding of the drive peg in the oblong aperture of the other of said levers namely either the lever for locking from the inside or the lever for locking from the outside.
In one particular embodiment, the lock comprises an additional lever for automatically unlocking from the outside when opened from the inside, said additional lever being mounted so that it can pivot on said second axle and comprising a first branch capable of cooperating with the interior door handle, said additional lever cooperating with the lever for locking from the outside to cause it to pivot into its unlocked from the outside position when the interior door handle is actuated. In this case, said additional lever may comprise a second branch capable of cooperating with an interior lock stalk to cause the lever for locking from the outside to pivot into its locked from the outside position when the lock stalk is actuated into its locked from the outside position.
According to another characteristic, the additional lever and the lever for locking from the outside are coupled in terms of rotation in the unlocked from the inside position and are uncoupled in terms of rotation in the locked from the inside position. In this case, the additional lever may comprise a third roughly L-shaped aperture, a first part of which corresponds to said second oblong aperture of the lever for locking from the outside and a second part of which corresponds to the first oblong aperture of the lever for locking from the inside, in the locked from the inside position, said third aperture having the aforementioned drive peg passing through it. As a preference, the additional lever is interposed between the lever for locking from the inside and the lever for locking from the outside.
Advantageously, the electromechanical locking/unlocking device is capable of reacting to an unlocking signal so as to cause the lock to move from a deadlocked condition into a condition in which it is unlocked from the inside and from the outside.
The supply of electric current to the electric actuating device may be obtained using a switch which is normally open and the closure of which is brought about in response to the transmission of the unlocked signal, this switch closing an electric circuit that supplies the electric actuating device with power.
As a preference, the electronic recognition device is supplied with electrical power only during the opening action exerted on the door handle by the user. This thus avoids powering the electronic recognition device constantly and it needlessly consuming energy.
To this end, the supply of electric current to the electronic recognition device can be achieved using a control system such as a microswitch which is normally open, closure of which is brought about by said opening action exerted on the door handle, this microswitch closing a circuit for supplying the electronic recognition device with electrical power.